package org.jaronsource.framework.util;

public final class MD5 {

	private static final int S11 = 7;

	private static final int S12 = 12;

	private static final int S13 = 17;

	private static final int S14 = 22;

	private static final int S21 = 5;

	private static final int S22 = 9;

	private static final int S23 = 14;

	private static final int S24 = 20;

	private static final int S31 = 4;

	private static final int S32 = 11;

	private static final int S33 = 16;

	private static final int S34 = 23;

	private static final int S41 = 6;

	private static final int S42 = 10;

	private static final int S43 = 15;

	private static final int S44 = 21;

	private static final byte[] PADDING = { -128, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };

	private String digestHexStr;

	private byte[] buffer = new byte[64]; // input buffer

	private long[] count = new long[2];

	private byte[] digest = new byte[16];

	private long[] state = new long[4]; // state (ABCD)

	public MD5() {
		md5Init();
		return;
	}

	public static String toMD5( String source ) {
		MD5 md5 = new MD5();
		return md5.getMD5ofStr( source );
	}

	private String getMD5ofStr( String inbuf ) {
		md5Init();
		md5Update( inbuf.getBytes(), inbuf.length() );
		md5Final();
		digestHexStr = "";

		for ( int i = 0; i < 16; i++ ) {
			digestHexStr += byteHEX( digest[i] );
		}

		return digestHexStr;
	}

	private void Decode( long[] output, byte[] input, int len ) {
		int i;
		int j;

		for ( i = 0, j = 0; j < len; i++, j += 4 ) {
			output[i] = b2iu( input[j] ) | ( b2iu( input[j + 1] ) << 8 ) | ( b2iu( input[j + 2] ) << 16 ) | ( b2iu( input[j + 3] ) << 24 );
		}

		return;
	}

	private void Encode( byte[] output, long[] input, int len ) {
		int i;
		int j;

		for ( i = 0, j = 0; j < len; i++, j += 4 ) {
			output[j] = (byte) ( input[i] & 0xffL );
			output[j + 1] = (byte) ( ( input[i] >>> 8 ) & 0xffL );
			output[j + 2] = (byte) ( ( input[i] >>> 16 ) & 0xffL );
			output[j + 3] = (byte) ( ( input[i] >>> 24 ) & 0xffL );
		}
	}

	private long F( long x, long y, long z ) {
		return ( x & y ) | ( ( ~x ) & z );
	}

	private long FF( long a, long b, long c, long d, long x, long s, long ac ) {
		a += ( F( b, c, d ) + x + ac );
		a = ( (int) a << s ) | ( (int) a >>> ( 32 - s ) );
		a += b;

		return a;
	}

	private long G( long x, long y, long z ) {
		return ( x & z ) | ( y & ( ~z ) );
	}

	private long GG( long a, long b, long c, long d, long x, long s, long ac ) {
		a += ( G( b, c, d ) + x + ac );
		a = ( (int) a << s ) | ( (int) a >>> ( 32 - s ) );
		a += b;

		return a;
	}

	private long H( long x, long y, long z ) {
		return x ^ y ^ z;
	}

	private long HH( long a, long b, long c, long d, long x, long s, long ac ) {
		a += ( H( b, c, d ) + x + ac );
		a = ( (int) a << s ) | ( (int) a >>> ( 32 - s ) );
		a += b;

		return a;
	}

	private long I( long x, long y, long z ) {
		return y ^ ( x | ( ~z ) );
	}

	private long II( long a, long b, long c, long d, long x, long s, long ac ) {
		a += ( I( b, c, d ) + x + ac );
		a = ( (int) a << s ) | ( (int) a >>> ( 32 - s ) );
		a += b;

		return a;
	}

	private static long b2iu( byte b ) {
		return ( b < 0 ) ? ( b & ( 0x7F + 128 ) ) : b;
	}

	private static String byteHEX( byte ib ) {
		char[] Digit = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
		char[] ob = new char[2];
		ob[0] = Digit[ ( ib >>> 4 ) & 0X0F];
		ob[1] = Digit[ib & 0X0F];

		String s = new String( ob );

		return s;
	}

	private void md5Final() {
		byte[] bits = new byte[8];
		int index;
		int padLen;

		// /* Save number of bits */
		Encode( bits, count, 8 );

		// /* Pad out to 56 mod 64.
		index = (int) ( count[0] >>> 3 ) & 0x3f;
		padLen = ( index < 56 ) ? ( 56 - index ) : ( 120 - index );
		md5Update( PADDING, padLen );

		// /* Append length (before padding) */
		md5Update( bits, 8 );

		// /* Store state in digest */
		Encode( digest, state, 16 );
	}

	private void md5Init() {
		count[0] = 0L;
		count[1] = 0L;

		// /* Load magic initialization constants.
		state[0] = 0x67452301L;
		state[1] = 0xefcdab89L;
		state[2] = 0x98badcfeL;
		state[3] = 0x10325476L;

		return;
	}

	private void md5Memcpy( byte[] output,
							byte[] input,
							int outpos,
							int inpos,
							int len ) {
		int i;

		for ( i = 0; i < len; i++ ) {
			output[outpos + i] = input[inpos + i];
		}
	}

	private void md5Transform( byte[] block ) {
		long a = state[0];
		long b = state[1];
		long c = state[2];
		long d = state[3];
		long[] x = new long[16];

		Decode( x, block, 64 );

		/* Round 1 */
		a = FF( a, b, c, d, x[0], S11, 0xd76aa478L ); /* 1 */
		d = FF( d, a, b, c, x[1], S12, 0xe8c7b756L ); /* 2 */
		c = FF( c, d, a, b, x[2], S13, 0x242070dbL ); /* 3 */
		b = FF( b, c, d, a, x[3], S14, 0xc1bdceeeL ); /* 4 */
		a = FF( a, b, c, d, x[4], S11, 0xf57c0fafL ); /* 5 */
		d = FF( d, a, b, c, x[5], S12, 0x4787c62aL ); /* 6 */
		c = FF( c, d, a, b, x[6], S13, 0xa8304613L ); /* 7 */
		b = FF( b, c, d, a, x[7], S14, 0xfd469501L ); /* 8 */
		a = FF( a, b, c, d, x[8], S11, 0x698098d8L ); /* 9 */
		d = FF( d, a, b, c, x[9], S12, 0x8b44f7afL ); /* 10 */
		c = FF( c, d, a, b, x[10], S13, 0xffff5bb1L ); /* 11 */
		b = FF( b, c, d, a, x[11], S14, 0x895cd7beL ); /* 12 */
		a = FF( a, b, c, d, x[12], S11, 0x6b901122L ); /* 13 */
		d = FF( d, a, b, c, x[13], S12, 0xfd987193L ); /* 14 */
		c = FF( c, d, a, b, x[14], S13, 0xa679438eL ); /* 15 */
		b = FF( b, c, d, a, x[15], S14, 0x49b40821L ); /* 16 */

		/* Round 2 */
		a = GG( a, b, c, d, x[1], S21, 0xf61e2562L ); /* 17 */
		d = GG( d, a, b, c, x[6], S22, 0xc040b340L ); /* 18 */
		c = GG( c, d, a, b, x[11], S23, 0x265e5a51L ); /* 19 */
		b = GG( b, c, d, a, x[0], S24, 0xe9b6c7aaL ); /* 20 */
		a = GG( a, b, c, d, x[5], S21, 0xd62f105dL ); /* 21 */
		d = GG( d, a, b, c, x[10], S22, 0x2441453L ); /* 22 */
		c = GG( c, d, a, b, x[15], S23, 0xd8a1e681L ); /* 23 */
		b = GG( b, c, d, a, x[4], S24, 0xe7d3fbc8L ); /* 24 */
		a = GG( a, b, c, d, x[9], S21, 0x21e1cde6L ); /* 25 */
		d = GG( d, a, b, c, x[14], S22, 0xc33707d6L ); /* 26 */
		c = GG( c, d, a, b, x[3], S23, 0xf4d50d87L ); /* 27 */
		b = GG( b, c, d, a, x[8], S24, 0x455a14edL ); /* 28 */
		a = GG( a, b, c, d, x[13], S21, 0xa9e3e905L ); /* 29 */
		d = GG( d, a, b, c, x[2], S22, 0xfcefa3f8L ); /* 30 */
		c = GG( c, d, a, b, x[7], S23, 0x676f02d9L ); /* 31 */
		b = GG( b, c, d, a, x[12], S24, 0x8d2a4c8aL ); /* 32 */

		/* Round 3 */
		a = HH( a, b, c, d, x[5], S31, 0xfffa3942L ); /* 33 */
		d = HH( d, a, b, c, x[8], S32, 0x8771f681L ); /* 34 */
		c = HH( c, d, a, b, x[11], S33, 0x6d9d6122L ); /* 35 */
		b = HH( b, c, d, a, x[14], S34, 0xfde5380cL ); /* 36 */
		a = HH( a, b, c, d, x[1], S31, 0xa4beea44L ); /* 37 */
		d = HH( d, a, b, c, x[4], S32, 0x4bdecfa9L ); /* 38 */
		c = HH( c, d, a, b, x[7], S33, 0xf6bb4b60L ); /* 39 */
		b = HH( b, c, d, a, x[10], S34, 0xbebfbc70L ); /* 40 */
		a = HH( a, b, c, d, x[13], S31, 0x289b7ec6L ); /* 41 */
		d = HH( d, a, b, c, x[0], S32, 0xeaa127faL ); /* 42 */
		c = HH( c, d, a, b, x[3], S33, 0xd4ef3085L ); /* 43 */
		b = HH( b, c, d, a, x[6], S34, 0x4881d05L ); /* 44 */
		a = HH( a, b, c, d, x[9], S31, 0xd9d4d039L ); /* 45 */
		d = HH( d, a, b, c, x[12], S32, 0xe6db99e5L ); /* 46 */
		c = HH( c, d, a, b, x[15], S33, 0x1fa27cf8L ); /* 47 */
		b = HH( b, c, d, a, x[2], S34, 0xc4ac5665L ); /* 48 */

		/* Round 4 */
		a = II( a, b, c, d, x[0], S41, 0xf4292244L ); /* 49 */
		d = II( d, a, b, c, x[7], S42, 0x432aff97L ); /* 50 */
		c = II( c, d, a, b, x[14], S43, 0xab9423a7L ); /* 51 */
		b = II( b, c, d, a, x[5], S44, 0xfc93a039L ); /* 52 */
		a = II( a, b, c, d, x[12], S41, 0x655b59c3L ); /* 53 */
		d = II( d, a, b, c, x[3], S42, 0x8f0ccc92L ); /* 54 */
		c = II( c, d, a, b, x[10], S43, 0xffeff47dL ); /* 55 */
		b = II( b, c, d, a, x[1], S44, 0x85845dd1L ); /* 56 */
		a = II( a, b, c, d, x[8], S41, 0x6fa87e4fL ); /* 57 */
		d = II( d, a, b, c, x[15], S42, 0xfe2ce6e0L ); /* 58 */
		c = II( c, d, a, b, x[6], S43, 0xa3014314L ); /* 59 */
		b = II( b, c, d, a, x[13], S44, 0x4e0811a1L ); /* 60 */
		a = II( a, b, c, d, x[4], S41, 0xf7537e82L ); /* 61 */
		d = II( d, a, b, c, x[11], S42, 0xbd3af235L ); /* 62 */
		c = II( c, d, a, b, x[2], S43, 0x2ad7d2bbL ); /* 63 */
		b = II( b, c, d, a, x[9], S44, 0xeb86d391L ); /* 64 */

		state[0] += a;
		state[1] += b;
		state[2] += c;
		state[3] += d;
	}

	private void md5Update( byte[] inbuf, int inputLen ) {
		int i;
		int index;
		int partLen;
		byte[] block = new byte[64];
		index = (int) ( count[0] >>> 3 ) & 0x3F;

		// /* Update number of bits */
		if ( ( count[0] += ( inputLen << 3 ) ) < ( inputLen << 3 ) ) {
			count[1]++;
		}

		count[1] += ( inputLen >>> 29 );

		partLen = 64 - index;

		// Transform as many times as possible.
		if ( inputLen >= partLen ) {
			md5Memcpy( buffer, inbuf, index, 0, partLen );
			md5Transform( buffer );

			for ( i = partLen; ( i + 63 ) < inputLen; i += 64 ) {
				md5Memcpy( block, inbuf, 0, i, 64 );
				md5Transform( block );
			}

			index = 0;
		}
		else {
			i = 0;
		}

		// /* Buffer remaining input */
		md5Memcpy( buffer, inbuf, index, i, inputLen - i );
	}
}